Already threatened with extinction, Wild Pacific salmon about to spawn in British Columbia are facing an uphill battle in the aftermath of a landslide
when Gord Sterritt walked to the dusty edge of a cliff in western Canada last summer, he saw a disaster unfolding in the frothy waters below. In December 2018, a natural landslide had caused large chunks of rock to fall from the steep canyon walls that hem in the northern sections of British Columbia’s Fraser River.
The crashing boulders – 75,000 cubic meters of rock – created an impassable barrier. But because of the remote location, the damage wasn’t discovered until the following June: just as millions of wild Pacific salmon were beginning to spawn up the river.
“When I saw it, I realized what we were up against,” said Sterritt. “The magnitude was just … awe-inspiring. And not in a good way.”
The fallout from the rockslide could not have come at a worse time. Wild Pacific salmon populations had already suffered steep and seemingly irreversible declines over the years; biologists openly muse about a future without the fish.
Government work crews, aided by local First Nations, sprang into action, deploying nets, trucks, drones, and dynamite in a frantic effort to help the salmon pass through the barrier.
Working through the dry summer heat at the site of the slide, known as Big Bar, as many as 100 people labored from early morning until dusk, clearing debris and rescuing stranded – and incredibly weakfish. Helicopters were brought in to airlift as many over the waterfall as possible.
Chinook, the hardiest type of salmon, made it through the frothy falls first, taking shelter in eddies to regain their strength before hurling their bodies into and over rocks. As crews cleared more space in the river, sockeye and pink salmon began clearing the barriers. In all, nearly 250,000 salmon successfully traversed the landslide area – with another 30,000 flown in by helicopter – a long way off the millions that normally make the journey.
Almost a year later, as the salmon return once more for their annual spawn, significant debris remains in the river.
“We knew from the start that this is a very difficult place to work and there’s a massive amount of material that has landed in this river,” Fisheries and Oceans Canada project leader Gwil Roberts said recently.
There are glimmers of hope in the protracted rescue mission: a pneumatic tube – called a Whooshh Passage Portal and nicknamed the “salmon cannon” – will soon be installed along the canyon walls to help move fish over the debris. A concrete fish ladder, constructed from hundreds of cement blocks, will also make the journey easier. And a convoy of trucks will be on standby to shuttle the fish over the barrier if things do not go as planned.
An exhausting journey
In some ways, the sustained effort by workers to save the fish, drawing on all possible resources, is dwarfed by the journey many salmon undergo at the end of their lives.
As their biological clock kicks in, salmon begin an exhausting journey from the Pacific coast to the rivers and streams of their birth – sometimes traveling more than 1,000km (600 miles). They are guided by magnetic fields and their keen sense of smell.
For a brief period, even the smallest streams are overwhelmed by tens of thousands of fish, transforming the tranquil bodies of water into a flurry of life.
“They’re splashing around, they’re chasing each other. It feels like the river is just pulsing with life,” said the Vancouver-based salmon researcher Vanessa Minke-Martin. “It’s a really magical thing to see.”
But the journey has a devastating impact on their bodies. From the moment they first enter freshwater, they stop eating and their bodies begin to decay and weaken. If they make it to a calm location in a stream, they reproduce and await their inevitable death within days.
Even reaching the site of the Big Bar landslide is a miracle: the fish need to travel more than 200 miles from the mouth of the Fraser River, running against the current the whole way. Some continue for another 400 miles to reach the streams where they were born.
Because of their unique life – born in freshwater, migrating to the ocean and living for years in the salty waters, only to return home to reproduce and die where they hatched – salmon have deep integration with nearly everything they interact with. First Nations have long understood the importance of that interaction. Indigenous communities that thrived nearly always did so because of their proximity to coveted salmon rivers.
“We used to hear stories of people walking across the river on the backs of fish there were so many,” said Sterritt, of the legendary bounty, harvested and smoked for the winter or traded with other communities.